An anesthetic evaporator has been known, in which the a gas flow entering a gas entry pipe branch of the anesthetic evaporator is divided into a so-called bypass gas flow and an evaporator chamber gas flow. The two gas flows are again united at a gas outlet pipe branch. The bypass gas flow returns directly to the gas outlet pipe branch via a bypass line, while the evaporator chamber gas flow is enriched with anesthetic vapor up to the saturation limit in an evaporator chamber. Different anesthetic concentrations can be set by changing the ratio of the two gas flows in relation to one another. Such an anesthetic evaporator has become known from EP 220 258 B1.
A wick, which is rolled up helically, is immersed into liquid anesthetic and through which the gas to be saturated flows from the outside to the inside, is located within the evaporator chamber. The liquid anesthetic rises in the wick by capillary action and is distributed over the entire surface of the wick. The wick surface must be dimensioned to be such that complete saturation of the flow in the evaporator chamber with anesthetic vapor is still reached at the maximum flow through the evaporator chamber. However, a large wick surface leads to a larger evaporator chamber volume in the prior-art anesthetic evaporator. However, not only does a large evaporator chamber volume increase the volume of the anesthetic evaporator, but also has an adverse effect on the necessary constancy of the anesthetic concentration during changes in pressure, which occur during respiration. To compensate this effect of the changes in pressure on the anesthetic concentration released, a so-called pressure compensation line, with which the gas enriched with anesthetic shall be prevented from flowing back into the bypass gas flow, is provided at the inlet of the evaporator chamber. Thus, the pressure compensation line must also be made correspondingly longer in case of a large evaporator chamber volume, which leads to an additional increase in the volume of the anesthetic evaporator.